Research into polynomial image sets has strong connections with the
PI-theory. In particular, a polynomial identity is a polynomial whose
image set is \(\lbrace 0\rbrace \) , and a central polynomial is a
polynomial whose images are central elements (in matrix algebras,
central elements are scalar matrices). The methods of working with PI
are set out in [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]},
for more detailed exposition of PI theory and related
references see [17]}. For combinatorial questions see [18]}.
